EP 0078252 B1 19871209 - ELECTRONIC WELDING DEVICE
Title (en)
ELECTRONIC WELDING DEVICE
Publication
Application
Priority
- AT 229582 A 19820614
- AT 362282 A 19820930
- AT 386782 A 19821021
- AT 456581 A 19811027
Abstract (en)
[origin: EP0078252A2] 1. An electronic welding apparatus including a primary controlled switching mode power supply including a inverter in form of a halfsemiconductor stage (3), said inverter being connected to a power line rectifier (2) and controlled through an analog control circuit (6) in dependence on the arc current and/or to the arc voltage, wherein the output is connected through a transformer (4) with a welding rectifier (5), with two electrical current/voltage converters (7) for the arc voltage and the arc current, the nominal value input of the analog control circuit (6) being connected with the output of a microprocessor control (10) provided for adjusting the nominal value of the one arc-magnitude or of both arc-magnitudes and for watching the welding and the analog control circuit effecting a comparison nominal-actual value, for generating in dependence thereto an error signal (28) which is supplied to a pulse width modulator (27) of the semi-conductor-switching stage (3), which comprises transistors (21, 23; 29-32) as switch and being designed as single-ended buck regulator with an asymmetric half-bridge circuit or as push pull full bridge, characterized in that for monitoring the saturation voltage of the transistors (21, 22) are provided comparators (49, 50), that for limiting the collector current of the transistors (21, 22) are provided two comparators (43, 44) the outputs of the first and second comparators (49, 50, 43, 44) are supplied to the set-input (S) of two flip-flops (45, 46), the outputs of which are supplied through amplifiers (47, 48) to driver stages (25, 26) of the transistors (21, 22), for switching them off in an excessively high saturation voltage or an excessively high collector current occur and wherein for delimiting the current rise time of the collector currents of the switching transistors (21, 22) is provided an additional transformer in the secondary circuit of the transformer (4), having a primary and secondary coil arranged in series and coiled in opposite direction so that due to the counter voltage of the secondary coil, the current rise is delimited in dependence on the load and thus on the welding current, and wherein the output of one of said two flip-flops (45, 46) is each connected with the set-input (S) of the other one of said two flip-flops (45, 46), so that, when one of said two flip-flops is set, simultaneously also the other one of said two flip-flops is set.
IPC 1-7
IPC 8 full level
B23K 9/09 (2006.01)
CPC (source: EP)
B23K 9/091 (2013.01)
Designated contracting state (EPC)
BE CH DE FR GB IT LI LU NL SE
DOCDB simple family (publication)
EP 0078252 A2 19830504; EP 0078252 A3 19831214; EP 0078252 B1 19871209; DE 3277803 D1 19880121
DOCDB simple family (application)
EP 82890153 A 19821025; DE 3277803 T 19821025